The principal objective of this investigation is to determine the clinical and biological significance of cell surface marker analysis in the diagnosis, prognosis and developmental sequence of hematopoietic neoplasias. The principal hytothesis underlying this work is that the different neoplastic proliferations represent malignant deviations "frozen" at various stages of development along the line of differentiation of normal B, T and monocytic cells. The methodology to be employed will enable the recognition of B, T, K, monocytic and "null" cell types involved in leukemias and lymphomas. Moreover, the "null" cell type of lukemias and lymphomas will undergo further dissection into those with and those without high levels of activity of the enzyme terminal deoxynucleotidyl transferase (Tdt), in collaboration with other investigators. It is hoped that the addition of new reagents (cytoplasmic IgM, antisera to "Ia like" antigens, peanut lectin binding and anti-leukemic sera) will help further in the recognition of normal stages of development and their neoplastic counterparts. Assay of helper and suppressor capacities as well as induction of differentiation by tumor promoters, will test and challenge the developmental sequences proposed for the different cell lineages. Correlation of surface marker and functional analysis as proposed here, with clinical parameters and other studies carried out by collaborating investigators in this cancer center, will allow an in-depth analysis of patients with hematopoietic neoplasias.